Stripper



STRiPPER Edward C. Peterson, Reading, and Joseph Calabrese, Pottstown, Pa., assignors to Birdsboro Steel Foundry and Machine Company, Birdsboro, Pa., a corporation of Delaware Application August 15, 1956, Serial No. 604,137

4 Claims. (Cl. 22-95) The present invention relates to strippers for removing hig-end-up ingots from ingot molds.

The present application is a continuation-in-part of our co-pending application, Serial No. 345,382, filed March 30, 1953 for Stripper.

A purpose of the invention is to lock the ingot mold to the stripper and accomplish the stripping by a single control means.

A further purpose is to use a common hydraulic system to first lock the ingot mold to the seat of the stripper and then force the pintle through the bottom of the mold to detach the ingot.

A further purpose is to secure the ingot mold firmly against the stripper plate or ingot mold seat during stripping so that the ram is not likely to bend.

A further purpose is to lock the ingot mold against the ingot mold seat resiliently so as to allow for difierence in the positions of ingot mold lugs.

A further purpose is to avoid fixed arms on ingot mold strippers.

A further purpose is to gripping arms down and in by a raise the pintle by an upper ram cylinder.

A further purpose is to provide links which at their upper ends pivotally connect to the outsides of the arms and at their lower ends have pivot mounting on the frame outside the arms.

A further purpose is to make the pivot mounting resilient, preferably on a rocker urged against a stop by a spring and yielding away from the stop.

A further purpose is to provide a stop which engages the lower ram or its yoke, permitting application of higher pressure to the pintle.

A further purpose is to operate the common hydraulic means by a system including a low pressure high volume pump and a high pressure low volume pump and to cut off operation of the low pressure high volume pump when the pressure rises, due for example to the fact that the ingot is a sticker.

A further purpose is to pivot the gripping arms on a yoke which is itself pivotally supported on the lower ram, to allow for inequality in lug location on the ingot mold.

Further purposes appear in the specification and in the claims.

In'the drawings we have chosen to illustrate one only of the numerous embodiments in which our invention may appear, selecting the form shown from the standpoints of convenienc in illustration, satisfactory operation and lear monstration of the principles involved.

Figure l is a front elevation of the ingot stripper of bring the upper ends of the lower ram and then to of a common hydraulic the invention.

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Figure 4 is a diagram of a hydraulic and electrical arrangement which may be used in the invention.

Describing in illustration but not in limitation and referring to the drawings:

Big-end-up ingots are being widely used, and in some cases they are diffieult to remove from the ingot mold. Prior art strippers have required separate operations for holding the ingot mold and for forcing the ingot away from the mold. One of the advantages of the present invention is that the same operation by the operator grips the ingot mold and also loosens the ingot.

Inprior art strippers intended for big-end-up ingots, the mgot mold has often been positioned relatively loosely against the stripper, and fixed arms have been used for holding the ingot mold. When stripping takes place the ingot mold has moved upwardly with respect to the mechanism, and at the sane time in some cases has tended to incline, and this has resulted in bending the ram of the stripper, seriously damaging the mechanisrn.

In the prior art devices also operation has not always been effective when the lugs or other gripping surfaces on the ingot mold have deviated widely from their normal size. In accordance with the present invention, the gripping of the ingot mold is resilient and the ingot mold lugs needs not be accurate in order that the device can function effectively. In accordance with the invention, common hydraulic means are employed to grip the ingot mold and to accomplish the stripping. Preferably the same hydraulic cylinder having two rams is used for both purposes.

In the preferred embodiment the upper ram accomplishes stripping and the lower ram grips the ingot mold.

Arms extend above the ingot mold seat, and are moved downwardly and inwardly at the top as the ingot mold is gripped. This is preferably accomplished by links pivotally mounted at their lower ends outside the arms. The pivotal mounting is preferably yieldable, desirably due to the motion of rockers away from stops against the action of springs. The arms pivot on a yoke pivotally supported on the lower ram to allow for unequal lug sizes on the ingot molds.

The device automatically supplies the necessary force to release the ingot. Thus there is preferably a source of high volume low pressure hydraulic fluid and a source of low volume high pressure hydraulic fluid, and when the pressure rises, as for example when the ingot is a sticker, the source of high volume low pressure fluid is suitably cut out and the source of low volume high pressure fluid acts to release the ingot. As the pressure drops again the source of high volume low pressure fluid again operates.

It is of course very desirable that the lower ram be effective before the upper ram operates, and this is readily accomplished due to the force of gravity pulling down on the lower ram. The lower ram or yoke then encounters ingot stripping lugs on the ingot mold and these provide resistance against which pressure can develop to strip the ingot.

An ingot mold 20 of the big-end-up type having lugs 21 near the bottom for gripping and having an open top and an open bottom rest on a plate or ingot mold seat 22 which is suitable at or slightly above the level of the floor 23.

Suitable adjustable locating abutments re provided on the seat to place the ingot centrally above the stripper, the abutments desirably being mounted on arms 26 which in turn are adjustably mounted in brackets 2.7, the arms being released for adjustment by set screws 2%. The locator abutments desirably extend in diagonally from the four corners to engage an ingot suitably or" octagonal or other fluted form.

The locator abutments are desirably beveled at the inside upper edge 3% to aid in inserting the ingot mold as it is lowered by the crane.

In order to anchor the ingot mold on the seat, a pair of opposed gripping arms 31 are provided which in the inactive position have hooked ends 32 extending above the seat and outside the line of the lugs 21 at a position above the lugs. The arms in this position engage near and preferably below their gripping ends but intermediate their ends against stops 33 outside the arm-s, and suitably below the stops pivotally connect at 34 with the upper ends of links 35 extending generally vertically. The lower ends of the links outside the arms are pivotally supported at 36.

The pivot supports 36 are desirably yieldable and are mounted on rocker arms 37 rotatable with shaft 38 which is journalled in frame 40. The shaft 38 at its opposite ends carries rocker arms 41 which in inactive position engage against stops d2 secured to the frame. The outer ends of the rocker arms ill are pivotally connected at 43 to the lower ends of spring pull rods 4-4 which pass up through slots in the stops 42. The pull rods are surrounded by spiral compression springs 45 which are compressed between the stationary stops 42 and spring compression nuts 45 threaded on the upper ends of the pull rods. Thus in the inactive position the pivot support 36 is a stationary pivot mounting for the links 35, but it is capable of yielding by yielding of the springs to allow the pivot support 36 to move outward as the rocker arms '7 swing.

The arms 31 at their lower ends are pivotally connected at 47 on the outer ends of a yoke 48 which is pivotally mounted on a pin 4-9 on the lower end of hydraulic ram b in cylinder 51 whose axis extends in the direction of the major axis of the ingot mold. The ram is provided at 52 for piston rings, near its upper end, and on its side surface near the lower end is engaged by packing 53, so that fluid pressure for main ram operation is introduced above the ram at 54 and fluid pressure for pull back operation is introduced in the space 55 between the ram and the cylinder and between the piston rings 52 and the packing 53.

A stop 56 located below the yoke limits the downward movement of the yoke if the ingot lugs fail. Lugs 31' on the sides of the upper ends of the arms 31 engage the stripper frame if there is excess angularity on the yoke due to its pivoting on the piston rod.

Suitably at the center of the ingot mold seat 22 a vertical opening 57 is provided, through which extends upwardly a pintle 53 which acts to strip the ingot from the mold. The pintle at its lower end has a head 60 which is outwardly flanged and has at the bottom a spherical surface 61 which engages in a spherical seat 62 of a chuck 63 on the upper end of upper ram 64 which operates in the same cylinder 51 above the lower ram. The head 6ft is held in place by a check coilar 65 bolting into the top of the upper ram. The ball and socket joint on the pintle corrects for misalignment of the stripper opening in the ingot mold.

The upper ram at its lower end is provided for piston rings at 5-5. At its upper end the sidesurface is engaged by packing 67. The main operating pressure of the upper ram is e erted from below by fluid entering connection but the pull back pressure is exerted by fluid entering the space 553 the space between the upper ram and the cylinder and between the piston rings 66 and the upper packing 6'7.

The upper ram desirably has a recess '73 at the center its lower end and the lower ram desirably has an upward extension 71 which fits into the recess, providing a dashpot which cushions impact between the rams.

in operation, assuming that the mechanism has been returned by the pull backs to the position of Figure 2, with 4 pintle lowered and the arms raised and positioned outwardly, an ingot mold is placed on the ingot mold seat with the lugs 21 disposed outwardly toward the arms 31, and containing a big-end-up ingot to be stripped.

The operator then admits hydraulic fluid through the connection 54 to the cylinder between the rams. Since the effect of gravity aids the travel of the lower ram, and since the ingot is pressing down against the pintle, the lower ram travels downward before upward movement of the upper ram, since both rams are acting from the same diameter under the same hydraulic pressure. As the lower ram move-s down, it pulls the arms 31 down and as the arms move down the links 35 cause the arms to swing in about the pivot support 36 as a center, swinging about the pivotal connections 47 at the bottom of. the arms. This occurs until resistance is encountered by on gagement of the arms against the side of the ingot moid, and when the arms engage the side of the ingot mold before the hook ends 32 seat on the lugs the pivotal supports 36 are forced outward as the arms are pulled further down, by turning of the rocker arms 37 and 41 outward against the action of springs 45. Eventually the arms 31 seat and engage against the lugs 21, holding the ingot mold. If the lugs are uneven, the yoke shifts slightly about its pivot on the lower ram to correct for this. Further pressure then causes the upper ram and the pintle to travel upward thus stripping the ingot from the ingot mold. If the stripper, opening in the ingot mold is slight- 1y misaligned, the pintle can shift at the ball and socket joint.

It will be evident that this is accomplished by a single control and a single application of pressure through the connection at 54.

Thus it will be seen that common hydraulic means move the pintle up and move the arms in and down, and that the arms readily adjust to variations in the shape or position of the lugs on different ingot molds, due to the swinging of the rockers which mount the lower ends of the links.

It will further be evident that the lower ram moves downwardly before the upper ram moves upwardly, and thus the ingot mold is held in place before the stripping action occurs.

It will further be evident that the difliculty encountered in the prior art, by which the arms allowed the ingot mold to rise as the stripping force was applied and the ingot mold was likely to tilt and bend the pintle, is not encountered in the present device, since the ingot mold remains firmly seated during the stripping.

In order to speed up the operation without requiring excessive pumping capacity, it is preferable to employ two pumps, one a low pressure high volume pump and the other a high pressure low volume pump, and to shift the operation automatically when resistance is encountered.

Figure 4 illustrates diagrammatically a system which can be employed. Thus hydraulic fluid is withdrawn by a pipe 72 from a suitable source through parallel pipes 73 and 74, one of which contains a high volume low pressure pump 75 and the other of which contains a low volume high pressure pump 7 both normally pumping toward the pipe 54 connected to the hydraulic cylinder 51. The pumps are both driven by an electric motor 77 from electric supply lines 78. Two-position solenoid valve 80 is placed on the output side of high volume low pressure pump 75, and in its normal or deenergized position it permits fluid to flow to pipe 54. When the solenoid 81 is energized by closing of normally open pressure switch 32 on the attainment of abnormally high pressure in the pipe 54, solenoid valve 86 shifts to connect the output of high volume low pressure pump 75 to bypass 83, which returns it to the pump, and to close pump 75 off from pipe 54. As long as any resistance is encountered such as from a sticker ingot, the low volume high pressure pump alone acts, but whenever there is no abnormal resistance, both pumps act.

While the device of the invention has been shown with the pintle upwardly directed to strip big-end-up ingots, it may also be inverted and suspended above the ingot mold to strip big-end-down ingots.

In view of our invention and disclosures, variations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art, to obtain all or part of the benefits of our invention without copying the structure shown, and we, therefore, claim all such insofar as they fall within the reasonable spirit and scope of our claims.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

1. In a stripper for removing an ingot from an ingot mold, including arms extending on either side of the ingot mold and adapted to grip the ingot mold, and a support connected to the arms at their ends remote from the ingot mold, the combination of links located outside the arms and extending generally longitudinally of the arms, a

pivoted connection between the end of each link, adjacent the ingot mold and one of the arms, a pivot mounting for the other end of each link, lever means resiliently urged in one direction supporting the pivot mounting for the other ends of the links and yielding to allow the pivot mounting to move outward under load conditions, a hydraulic cylinder extending vertically between the arms and between the ingot mold and the support, a first ram operating vertically in the bottom of the cylinder, operatively connected to the support, a second ram operating vertically in the top of the cylinder, and pusher means extending vertically upward from the second ram and adapted to dislodge an ingot.

2. A stripper of claim 1, in which the resilient lever means comprises rockers pivotally mounting the other ends of the links, stops against which the rockers normally engage, and springs urging the rockers against the stops and yielding to permit the ends of the links remote from the ingot mold to move upward.

3. A stripper of claim 1, in which the pusher means comprises a pintle and a ball and socket joint between the second arm and the pintle.

4. In a stripper for removing an ingot from an ingot mold, including arms extending on either side of the ingot mold and adapted to grip the ingot mold, and a support connected to the arms at their ends remote from the ingot mold, the combination of links located outside the arms and extending generally longitudinal of the arms, a pivoted connection between the end of each link adjacent the ingot mold and one of the arms, resilient pivot mountings for the other ends of the links permitting the pivots of the other ends of the links to move outward under load, a hydraulic cylinder extending vertically between the arms and between the ingot mold and the support, a first ram operating vertically in the bottom of the cylinder, pivotally connected to the support, whereby the support can rock, a second ram operating vertically in the top of the cylinder, and pusher means extending vertically upward from the second ram and adapted to dislodge an ingot.

References Cited in the file of this patent UNITED STATES PATENTS 526,093 Aiken Sept. 18, 1894 2,362,696 Hively Nov. 14, 1944 

